<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		<button onclick="foo()">隔10s关闭页面</button>

		<button onclick="foo2()" id="btn2">倒数10s</button>
		<script>
			// setTimeout(要执行的代码,间隔时间)
			function foo() {
				setTimeout(function() {
					close();
				}, 10000);
			}

			var n = 10;

			function foo2() {
				if (n > 0) {
					n = n - 1
					btn2.textContent = "倒数" + n + "s";
					setTimeout(foo2, 1000);
				}
			}
		</script>
	</body>
</html>